Stability and deactivation of OER electrocatalysts: A review

Recently, H2 has attracted increasing attention as green energy carrier holding the possibility to replace fossil fuel-based energy sources and thereby reduce CO2 emissions. Green hydrogen can be generated by water electrolysis using renewable energies like wind and solar power. When it is combusted, only water forms as by-product. However, the efficiency of water electrolysis is hampered by the anodic oxygen evolution reaction (OER) because of the slow kinetics which leads to a high overpotential. Therefore, many catalysts have been developed for OER to facilitate the kinetics and reduce the overpotential. In addition to electrocatalytic activity, the stability of the catalysts is imperative for industrial application and has been intensively studied. In this review, we cover recent findings on the stability and deactivation mechanisms of OER catalysts. We discuss the correlation between OER activity and stability, methodologies and experimental techniques to study the stability and deactivation as well as the deactivation mechanisms, together with factors influencing stability. Furthermore, strategies for stabilizing and regenerating OER catalysts as well as methods to predict stability are summarized. Finally, the review highlights emerging methodologies yet to be explored and future directions of stability studies and the design of highly stable OER catalysts.